Circuit-protecting device.



E. 0. SCHWEITZER & N. J. CONRAD.

CIRCUIT PROTECIING DEVICE.

APPLICATION FILED MAY 22. IQII.

Patented Feb. 13, 1917.

)ifi/huw@ 1 'tiza/ga E. 0. SCHWEITZER L N. CONRAD.

CIRCUIT PROTECTING DEVICE.

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3 SHEETS-SHEET-2.

E. 0. SCHW'EITZER 8L N. J. CONRAD.

CIRCUIT PROTECTING DEVICE. APFLlcATloN FILED MAY22.191|.

Patented Feb.1s,1917.

3 SHEETS-SHEET 3- UNITED STATES PATENT OFFICE.

EDMUND 0. SCHWEITZER D NICHOLAS J. CONRAD, 0F CHICAGO, ILLINOIS, ASSGNOBS T0 SCHWEITZEB & CONRAD, A CORPORATION OF ILLINOIS.

CIRCUIT-PBOTECTING DEVICE.

Specification of Letters Patent.

ratented Feb. 13, 1917.

Application led'lay 22, 1911. Serial No. 628,804.

To all whom t may concern.'

Be it known that we, EDMUND O. SoHwErr- Zim and NICHOLAS J. CONRAD, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Circuit-Protecting Devices, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

Our invention relates to circuit protecting apparatus, and especially to a type of apparatus fitted for use upon circuits having very high potential and coming from very high capacity generators.

Devices of the kind of this application might be called extra high potential circuit openers.

In certain applications filed'by us, to-wit Serial No. 550,219, filed March 8, 1910; Serial No. 555,005, filed April 12, 1910; and Serial No. 581,000, filed Sept. 8, 1910, we have set forth certain extra high potential circuit opening or protecting devices having certain features of novelty which are therein claimed. In the present application we show devices of substantially the general type set forth. in oursaid other applications, together with certain novel features well adapted for use in connection with said apparatus, and also for use in connection with other apparatus.

The object of the present invention is to provide a simple, practical and effective circuit protecting device especially adapted for extra high potentials, to arrange for the easy assembling of the same to reduce the expense of construction, and at the same time to add to the efficiency and operative qualities of the apparatus.

More particularly the present invention is an improvement upon the structures-set out in those patents. The organization of the casing, fuse, are extinguishing liquid, and terminals, has been improved to provide a more efficient, economical, and practical structure. We have found that when the fuse, as previously constructed by us, is subjected to great overload, the resultant explosion is often so violent as to rupture the container and thus, even though the arc is extinguished, the structure is incapacitated for relilling or renewal, and is moreover, difficult tohandle. As it is impossible to foretell the violence of the blowing of the fuse,.

we have conceived the futility of trying to reinforce .the container sufficiently to withstand all shocks and have devised a way of reducing to a minimum the damage that can be done by providing a line weakness in the container which shall predetermine the point of rupture. Thusfalthough we cannot foretell when or how violently the fuse will be blown, we have predetermined where it will be ruptured. This insures uniform action and reduces the problem of breakage. It also provides greater security and certainty of action and tends to lower the cost of production and to increase the'ease of manufacture. i

In the accompanying drawings Figure 1 is a longitudinal section of a device of the class specified, embodying our present invention;

Fig. 2 is a similar longitudinal section of a modified form of device;

Fig. 3 is a similar sectionof a still different modification;

Fig. 4 is a view on an enlarged scale of an end portion of the device' of Fig. 3;

Fig. 5 is a top plan of the same;

Fig. 6 is a section taken on line 6--6 in Fig. 5;

Fig. 7 is a view of a port-ion of the end structure of the device of Fig. l;

Fig. 8 is a cross section taken on line 8-8 in Fig. 2;

Fig. 9 is a cross section taken on line 9 9 in Fig. 2;

Fig. 10 is a longitudinal section of another vmodification Figs. 11 and 12 are longitudinal sections of still different modifications;

Figs. 13 and 14 are cross sections taken respectively on lines 1?-13 and 14-14 in Figs. 12 and 11;

Fig. 15 is a longitudinal section of a still different modification.

The present invention provides a fuse device having a sleeve of insulation which is closed at both ends to form a liquid tight container for containing a body of arc extinguishing liquid. A fuse is supported in the'upper end of the container and this 'fuse is connected to a pair of metal ferrules mounted on the sleeve of insulation. These ferrules are connected to stationary terminals to put the fuse in the circuit to be-pro` tected. The container is provided with a lio - line of weakness outside of one of the termipresent structure we cause the container toA be ruptured instantly by blowing 0H the whole end so that lthe entire cross section is opened and the pressure is relieved instantly. Referring tothe device shown in Fig. 1,

'this device is a tubular casingl, made preferably of insulating material such for eX- ample as glass. rlhe upper end 2 of the casing or tube is provided with a conical opening or orifice in which is fitted a stopper or plug 3. When the device is made of glass the meeting faces of the orifice in the end 2 and the stopper 3 are ground in the usual way ofmaking ground glass surfaces, so that they will t closely and accurately together. This makes a tight joint or connection, and it umay be sealed by simply wetting the meeting surfaces of the stopper and end, the ground glass aifording this connection by reason of its peculiar character.

lmmediately below the top 2 is a reduced.

or weakened portion 4: in the form of an annular groove around the tube 1. 'lhe purpose of this weakened portion is to form a predeterminedv line of weakness for predetermining the point of fracture of the casing or tube 1 in case of a strong orespecially explosive operation of the circuit opening mechanism within the device.

Below the annular groove 4 is a metal collar 5, which surrounds the tube 1 and is cemented in place by-a layer 6 of cement. A metallic conductor 7 is arranged alongside of the collar or sleeve 5 and connected to the same by 'a binding screw 8. 'lhis connection orconductor 7 extends up across the end of the device and thence into and through the stopper 3 by way of a suitable orifice or aperture formed in the stopper.

lNithin the tube 1 is arranged afuse 9 preferably incased within a plug 10 of cork or other suitable substance, which substantially fills, the cross section of the tube 1 between the terminals of the fuse 9. The fuse 9 is connected to the end ta of the conductor 7, and the other end of the fuse is connected with a metallic strip 11, which extends down 'and connects with a spring 12, whose lower` end is secured at the bottom of the tube 1.

A preferred' arrangement for holding the lower end of the spring 12 comprises a Leitner tallic strip or wire 13, passing through the bottom 14, of the tube 1, and thence alongside of the same and upwardly to a metallic sheath or collar 15,' also cemented by cement 16 to the lower portion of the tube 1. 'The conductor 13 may be secured to this sleeve' or collar 15 in any way, as for example by soldering. Liquid is preferably introduced within the tube 1. -Ordinarily we prefer to have liquid substantially ll the tube. may be introduced through the opening in the top 2 by the aperture which is later closed by the stopper 8.

Certain general features ofv structure of the device just described have 4been set forth and claimed in one or more ofthe hereinbefore referred to prior applications. The invention of the present application relates more especially to the structure at the ends of the tube 1 by which the connectionswith the fuse and spring are made,'and also by which the liquid within the tube may be introduced and the weakened portion 4c for allowing breakage of the devicel Referringnext to the modication shown Vin Fig. 2 this device has the general features of the structure of the previously described device. The end portion 2a, however, is in form of a closed end of the tube 1, which end simply7 has an aperture for the admis- Asion of the conductor 7. ln other words there is no removable stopper in the end of this device, but on the contrary the tube is completely sealed at this end and the conductor 7 led through an opening in its closed end. f

rlfhe bottom 14a is substantially the same as that of the device in Fig. 1, except that said bottom is formed with an aperture for the admission of the liquid and this'aperture is later on sealed by heat as common in glass working, soas to form a closure 18.

ln order to introduce the mechanical devices into the interiorof the tube 1, said tube is desirably formed in two parts, which after the introduction of such devices are fused together along someline, as for erample the line 19. After this vthe liquid is introduced into the aperture inthe bottom 1awhich is then sealed. rl`he reduced portion i near'the vtop of the device is shown also in this figure.

Referring next to ,the modification shown in F ig. 3, the same general features 'of construction prevail but the'top and bottom are differently constructed. rlhe top 2b of this device is simply the open end of the tube 1. A metallic sleeve.a or collar or ferrule 20 is .arranged outside of the top 2b and is protop of the device coming into contact at its weakness for the fuse container.

.constructing the device.

edges with the knife edge 22, and a small quantity of solder 25 is used to fasten the rlid 24 in place. The amount of solder 25 required is very small and is such as to allow the lid 24 to be blown oli' in case the explosive force within the tube upon the operation of the device becomes excessive, thereby forming a device or member for venting the apparatus. The regulation or variation of the amount of solder used can of course bring about the proper variation or regulation in the amount of force necessary to blow off the top 24.

This knife edge 22 which is the line of attachment of the disk 24 and the solder connecting these parts, predetermine a line of It is apparent that the line of weakness may be otherwise secured and determined. Y The practical effect is that the container instead of being shattered between the terminals is ruptured outside of the terminals, i. e., by blowing off the top of the container externally to the fixed circuit terminals, which fixed terminals are therefore not disturbed and not subject to damage. Another advantage is that the liquid for extinguishing the arc will be retained in the container and will invariably be available to accomplish its purpose.

The conductor 7 is led through a suitable aperture in the lid 24 and this lid is also provided with a cut 26, Fig. 5, forming a lip 27 which can be bent up or down, and when bent into an upper position as shown in Fig. 6, allows the liquid to be filled into the tube 1. After that the lip 27 may be pressed down and then the cut 26 sealed by solder 28, as shown in Fig. 4.

The bottom of this modification is provided with a closure 29, having an aperture through which the end of the spring 12 is passed and secured. A cap 30 is fitted over the bottom end of the tube 1, and secured as by cement 31 in place, the closure 29 being preferably the bottom of cap 30. The bottom cap is rst secured in place and sealed to the glass tube with some suitable cementing substance, as for example shellac. Then the operating devices are placed within the tube, and then the top lid or cover secured in place, the arc extinguishing liquid such as carbon tetrachlorid filled in through the opening in the lid, and then said opening is closed and sealed.

The arrangements herein set forth for sealing the tube and securing the various instrumentalities of the device in place are very effective in preventing leaks of the liquid and affording eiicient methods of In the latter arrangement of Fig. 3 the connection of the fuse with the collar or ferrule 20 is complete by the connection of the wire 7 with the lid 24, so that the binding screw 8 may in'this case be omitted if desired. Instead of using shellac as the cementing material for securing the collars or ferrules in place we might use other'suitable cementing substance as for example a commercial adhesive cement called bakelite.

In Fig. 10 we have shown a modification in which the barrier or fuse inclosing member 10l is made of fiber which has the advantage of high insulating qualities and other operative and manufacturing features. This inclosure 10a is surrounded by a metal band 30, preferably of brass to prevent bursting or rupture of the fuse inclosure 10 upon the operation of the fuse. This ring 30 is in the nature of a strengthening band. In this arrangement, also, the spring 121 eX- tends up to the fuse inclosure 10, preferably filling substantially the entire length of the casing between its lower end and the cylindric inclosure 10a. This gives a maximum effective length of spring and at the same time simplifies and cheapens the construction, avoiding all unnecessary parts.

The arrangement shown in Fig. 11 has a duplex or composite tube or casing, the lower end of which is made of a glass tube 35, as herein before set forth, or a tube of other suitable material, and the other end kof which is made of a tubular. section formed of a brass or other metallic sleeve or sheath 36, and an inner tube section or sleeve 37, made of fiber or other suitable material. The brass tube section 36 is conveniently of the same size as the glass tube 35, while the inner fiber tube 37 is smaller than both the tubes 35 and 36,A so that it fits conveniently within the same. The inner section 37 is longer than the outer section 36, so that the inner section 37 extends into the upper portion of the glass or lower tube 35. This outer section 36 when made of brass or other metal can, it will be seen, be used as the terminal of the device, and to such end we have shown it provided with a binding screw 38 connected with a metallic connector 39 extended into the interior of the device and connected with the fuse arrangement.

The fuse proper is arranged within a block of solid material 40 which is preferably iber, and .this is desirably surrounded by a metal collar 4l, as referred to in connection with Fig. 10. The spring 1221 is desirably extended through the entire length between the lower end of the fuse with this surrounding member and the bottom of thc tubular casing, as mentioned in connection with Fig. 10.

The arrangement shown in Fig. 12 is generally similar to that of Fig. 11. It has an outer casing formed in part of a glass tube 35, a brass sheath or sleeve 36, and a liber sleeve 37a. In this arrangement, however, the sleeve 36a is larger than the glass tube 35, so that it extends down on the outer side of the same, Whereas'the ber sleeve 37' is of' greater thickness than the glass tube 35, so that its lower end can be formed into a thin tubular structure 4:1, extending down part wayinto the interior of the tube 35.

in both of these arrangements it willlbe seen the part of the outer casing immediately surrounding the device is substantiallya metallic structure with an insulating lining, which-of course will not break, should the operation of the fuse result in an eXplosion or arc.v At the same time the lower portion of the device is of insulating material so that it is light, and being preferably of glass is transparent, so as to show the condition of the fuse arrangement inside.

'The device of Fig. 15 involves a resistance arrangement which is `adapted for use in connection with the fuse portion of the structure. The particular form of ldevice shown for carrying out this feature involves a tubular casing adapted to be arranged outside of the metal cap 30h' at the lower end of the insulating tube 35. A metal ferrule 51 is arranged upon the, lower end of the tube 50 so as to close the same, if desired. Within theotube 50 is a cylindrical device or spool arrangement 52 which serves as a support and holder for a series of turns of wire 53, which are arranged to' serye as a highly inductive resistance or impedance,

vIE5

and this resistance is connected in series with the fuse circuit by being connected to changing current.

` sist through the device :Ecran appreciable length of time after the burning of the fuse, that during such time a large portion oi the energy of the circuit must be dissipated within the device in the incipient arc formed. Consequently any diminution of the energy of the circuit is beneficial. The reactance employed decreases the energy of the cir-l cuit by increasing the angle of lag, as shown bythe well known formulaz- Wattszllll cos. 0-

where t) is the angle of lag, E is the voltage,

`and l the current. rlhe edect just mentioned is independent of the C2 Rloss, the

latter being'always the same for a given current.

lit will be understood, of course that other naief/aa forms of .resistance can be used and the arrangement varied for including the resistl. A fuse deviceyhaving a removable lidy or cover, and a structure with a lmife edge coperating with said lid or cover and cementing material for holding the lid or cover in position and for allowingf'its removal upon exertion of pressure from within the device.

2. A device of the class specified, having a tubular casing, one of the ends of which is provided with a metal errule having a knife edge, a metal cap litted to the knife edge end of said ferrule and solder for holding the lid or cover in place alongside the line of connection between the lid or cover and said knife edge.

`3. rlhe combination of a tube a fuse therein and a venting device consisting of a thin disk at one end of the tube, and a' ferrule surrounding said end-of the tube,'said disk being soldered to the ferrule by solder adapted to permit said disk to be blown oli by the explosion of said fuse.

4. The combination of a tube a fuse therein, a metal ferrule surrounding an end por-n tion of said tube, a disk fitted across the end of the tube and ferrule so as to close the tube, said disk being soldered to said ferrule by solder adapted to permit said disk to be blown off by the explosion of said fuse.

5. rlhe combination of a fuse casing having a fuse chamber containing a fuse, a wall lportion of said chamber being detachably mounted .so as to permit its removal to vent said chamber by an. explosion of the fuse, and a fuse terminal extended through said removable wall portion and connected with said fuse. s

6. The combination of a fuse casing containing a' fuse and having a portion of the fuse chamber made removable, solder holding said removable wall portion normally in position, but permitting the same to be blown oli by the operation of the fuse, and a fuse terminal passing through said removable wall portion and connected with the fuse.

7. A device ofthe class specied,'having a containing case formed in part of a glass tube and in part of a metal tube having a lining ofv ber, the end of which extends into the interior of the glass tube, in combination with fuse devices, arranged Within said containing case and constructed to indicate operation by their condition.

'8. A device of the class specified, comprising a containing casing formed of a l glass tube and a metal tube lined with 'insulating material, a fuse connection connected to the metal tube and extended into the interior of the casing, a use inclosed in a body of solid material and arranged within the metallic portion of the containing casing, a coil spring connected to the fuse and arranged with .the glass portion of the casing, and arc extinguishing liquid within the casing.

9. The combination of a fuse casing made of fragile material, a fuse container holding a fuse and having its walls in close proximity to the walls of the casing, and a metal band surrounding said container.

10. The combination of a cylindric tubular casing made of fragile materiaha cylindric fuse container holding a fuse and arranged within said casing with its outer surface in proximity to the inner surface of "said casing, said container being made of heat insulating material, and a metal band surrounding said container and interposed between the same and the inner wall of said casing.

11. A device of the class described having a tubular casing having a portion of its length made of glass and another portion made of fiber and a metal ferrule surrounding the yportion vmade of iber. j

12. A device of the class described having a tubular casingvhaving a portion of its length made of glass and another portion made of liber and a metal errule surround ing the portion made offiber, and also a part of the glass portion.

13. In combination a tubular fuse casing, a fuse member adapted to be supported in said casing near one end of said casing, a liquid in said casing for extinguishing the arc caused by blowing of the fuse, closures for closing oft' the ends of said tubular fuse casing and forming a Huid tight container, and terminals on said casing for connecting said fuse in an electrical circuit, said container having a redetermined .line of weakness adjacent the se, said container being adapted to be ruptured at said line of weakness when the :fuse is violently blown so that the end of the` casing will be opened and will relieve instantly the explosive pressure.

14. In combination a tubular sleeve of insulation comprising a casing, a fuse in said casing supported near oneend thereof, an arc extinguishing 'medium in said casing for said fuse, means to close off the ends ofthe sleeve and to forni a Huid tight container, and a metallic errule at each end of the sleeve and mounted upon the outside thereof, said errules being connected to sai'd fuse and adapted to connect said fuse in an electrical circuit, said container having a predetermined line .of weakness adjacent the fuse, said line of weakness determining the point of rupture whnthe-fuse is violently blown, said line of weakness being determined at one end of the casing so that the rupture occurs external to the portion of the casing between the -ferrules and lreing therethrough for introducing an are l extinguishing mediumin said casing.

16. In combination a sleeve of insulation, a pair of metal ferrules embracing saidl sleeve, the lower end of said sleeve being closed, a disk for closing the other end of the sleeve, a fuse in said sleeve, said. being connected to said ferrule, said disk being soldered to the edges of the upper ferrule and having a filling o ening therein for introducing the liquid, said opening being adapted to be .permanently closed. to form a iuid tight container, said disk being adapted to be blown off at said soldered joint.

In witness whereof, we hereunto subscribe our naines this 18th day of May, A. D., 1911.`

EDMUNDO. SCHWEITZER. NICHOLAS J. CONRA Witnesses: p

A. LYDA JoNns, A. S. DENNIsoN. 

